Container gripping device having contact elements for braking

ABSTRACT

A device for gripping containers from above, which includes a frame which has a number of corners, twist-locks arranged close to each of the corners of the frame for gripping an upper corner of the containers, and contact elements connected to the frame, which elements are biased to a position located at least partly under the frame and which are adapted to brake the movement of the frame in the vicinity of a container when the frame is placed on the container. The presence of these contact elements allows loads on the frame to be reduced and noise nuisance to be minimized. The contact elements, which may be arranged in or on the frame and may protrude through openings formed in the frame, may be elastically deformable or may be pivotally connected to the frame. Compression springs and/or hydraulic cylinders may be arranged between the frame and the contact elements.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a device for gripping containers from above.

2. Description of the Related Art

Container gripping devices are generally known and, because the frame isgenerally adjustable, are usually referred to as spreaders.

Spreaders are applied for gripping containers during hoisting thereof,for instance during loading or unloading of container ships. Standardcontainers are provided for handling and anchoring thereof with grippingpoints on the corners, so-called corner castings. These corner castingsform reinforced corner points in which an elongate opening is formed.The gripping means of the frame, usually in the form of a so-calledtwist-lock, can grip in these openings.

A twist-lock consists here of a pin or shank with a hammer head on anouter end, which pin is received at its other outer end in a bush orsleeve, which is connected in turn to a rotating operating mechanism.The twist-lock can be rotated through 90 degrees by the operatingmechanism between a position in which the hammer head can be placed inthe elongate opening and a position in which the hammer head is fixed inthis opening.

Since during loading and unloading of containers the transport means onwhich or in which the containers are supplied and/or removed necessarilystands or lies still, the time involved herein is in principle costlyfor the transporter. It is therefore of great importance that this timeis minimized by processing the containers as quickly as possible. Thisentails gripping devices being carried to the containers at increasinglyhigher speed and hoisting speeds increasing more and more.

Owing to these higher speeds the loads which occur when the frame of thegripping device lands on the container are also becoming increasinglylarger. These greater loads result in increased wear and thus areduction in the life span of the different components of the device,while in addition the high loads result in considerable noiseproduction, both during landing of the frame on the container and at thebeginning of the hoisting movement, when the device is not yet fullyloaded. This noise results in nuisance, particularly in built-up areas.

It has already been proposed to reduce the loads on the gripping device,and thereby the noise nuisance, by applying spring-mounting and/ordamping. There are therefore spreaders on the market wherein eachtwist-lock with its operating mechanism is accommodated in a housing,which is movable in resilient and/or damped manner in the direction ofload relative to the frame, thus parallel to the shank of thetwist-lock. In one of the known spreaders rubber blocks arranged betweenthe housing and the frame are used as spring and/or damping elements,while in another known design use is made of hydraulic cylinders.

These known spreaders have the drawback that space is required forguiding of the housing in the frame, whereby the outer dimensions of theframe become larger at the position of the corners, and the frame willtherefore protrude outside the container(s). All lateral loads willhereby be absorbed by the frame, so that the chance of damage to thegripping device increases.

The spring and/or damping elements also take up space above thetwist-locks, whereby the construction height of the frame increases.This has consequences for the driving of the pivotable centring membersor “flippers” usually arranged on the corners of the frame. Because thisdrive is usually arranged on top of the frame, an increase in the frameheight results in a greater distance of the flippers from the drive, andtherefore a greater moment arm, so that the drive has to take a heavierform.

The stability of the construction is furthermore reduced by the floatingsuspension of the twist-locks, while the precision with which thespreader can be placed on a container likewise decreases.

Finally, owing to the increase in the dimensions of the frame in alldirections, the chance of damage thereto is increaseddisproportionately, since a spreader in loaded state, particularly whenit is hoisting a plurality of containers simultaneously, will never hangperfectly horizontally. A slightly inclining position, particularly atthe start of a hoisting movement, can result in the spreader becomingjammed, for instance in a cell of a container ship, whereby very highloads will occur which will soon result in damage.

SUMMARY OF THE INVENTION

The invention therefore has for its object to provide a containergripping device of the above described type, wherein these drawbacks donot occur. According to the invention this is achieved in such a deviceby at least one contact element connected to the frame, which element isbiased to a position located at least partly under the frame and whichis adapted to brake the movement of the frame in the vicinity of acontainer when the frame is placed thereon. By making use of one or morecontact elements connected to the frame for the purpose of braking theframe, and not using the twist-locks for this purpose, the twist-lockscan be built compactly into the frame in conventional manner.Furthermore, a stable and readily placeable spreader is thus obtained.

In order to distribute the loads over the whole frame, the grippingdevice preferably has a number of contact elements, each arranged in thevicinity of a corner of the frame.

A compact device is obtained when the or each contact element isarranged in or on the frame and protrudes through an opening formed inthe frame. The space available in the frame can thus be utilizedoptimally.

The or each contact element is preferably elastically deformable. Thedesired movement can thus be achieved with a minimum of components,whereby the chance of malfunction is relatively small.

It is on the other hand also possible for the or each contact element tobe pivotally connected to the frame. This produces a readilycontrollable and guidable movement of the contact elements.

The or each contact element is advantageously biased by spring meansarranged between the frame and the or each contact element. In thismanner the loads can be uniformly transferred to the surroundingconstruction during braking of the frame.

In order to absorb a part of the energy during braking of the frame, thedevice preferably has damping means arranged between the frame and theor each contact element. When these damping means are at least partlyaccommodated in an elevation formed on the frame, they can take arelatively large form, and thus produce a considerable damping withoutprotruding and being exposed to damage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a container gripping device according tothe invention in operation,

FIG. 2 is a partly cross-sectional end view according to arrow II inFIG. 1, in which the device is shown at the moment of contact with acontainer,

FIG. 3 is a partly cross-sectional end view corresponding with FIG. 2 ofthe device at the moment that the frame rests fully on the container,and

FIGS. 4 and 5 are detail views according to arrows IV and V in FIGS. 2and 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A gripping device 1 (FIG. 1) for picking up a container 2 from above isformed by a frame 3 which is suspended from a number of cables 5 trainedover pulleys 4. In the shown embodiment the frame 3 is embodiedtelescopically, with a main body 6 and two sets of inner and outertelescopic arms 7,8, although it will be apparent that the invention canbe applied equally well in a fixed frame.

On the end of each outer telescopic arm 8 is arranged a relatively highcross beam 9 which in each case has on its corners 10 gripping means inthe form of a twist-lock 11. In addition, centring members or flippers13 pivotable on shafts 12 are also placed on the corners.

Each twist-lock 11 is formed by a hammer-head bolt 14, the shank 18 ofwhich is received in a guide sleeve 15. At the top the shank 18 ofhammer-head bolt 14 is fastened in an operating sleeve or crank 16,which is connected in turn to an operating mechanism 22. Hammer-headbolt 14 can be rotated around an axis 17 by this operating mechanism 22,which does not form part of the present invention and will not befurther described here.

Situated on the free outer end of shank 18 is a hammer head 19 which isformed and dimensioned such that it can be placed in an elongate opening20 in a corner part or corner casting 21 of container 2, and can behooked fixedly in this opening 20 by being rotated through 90° on axis17.

Gripping device 1 is further provided in conventional manner with cornerrollers 23 for guiding frame 3 in small spaces, as well as a sensor 24which detects the movement of a feeler 25 and on the basis thereofdrives a locking mechanism for twist-lock 11.

In order to limit the loads on device 1 as much as possible duringlowering of frame 3 onto container 2, contact elements 26 are arrangedin the vicinity of corners 10 of frame 2, which elements are biased intoa position in which they protrude partly below the frame. In the shownembodiment each contact element 26 is formed by an L-shaped leg, an endpart 27 of which is fixed on the base 28 of cross beam 9, while the freeend part 29 protrudes through an opening 30 in this base 28. EachL-shaped contact element 26 is mounted rigidly here, but is given anarrowed form close to its end part 27, whereby this part is resilientlydeformable. In the unloaded situation each contact element 26 takes upthe position shown in FIG. 2, wherein end part 30 therefore protrudesbelow frame 3.

When frame 3 is now lowered onto a container 2 for hoisting, it is theprotruding end parts 30 of contact elements 26 which first come intocontact with the upper side of container 2. Contact elements 26 willherein bend upward under the influence of the weight of the loweringframe 3, whereby a part of the kinetic energy of frame 3 is absorbed andit is thus braked. The contact elements are dimensioned herein such thateven when the end parts 30 completely disappear into frame 3, theoccurring deformations are still in the elastic range, so that contactelements 26 will thus spring back when the load is removed.

In order to enable the absorption of an even greater part of the kineticenergy of frame 3, spring means 31 are also arranged between contactelements 26 and frame 3. These spring means 31 are formed here bycompression springs 32 placed around bolts 33 which are in turn mountedin base 28 of cross beam 9, protrude through the L-shaped legs and eachcarry a lock nut 34 on their free outer end.

Both the spring means 31 and the contact elements 26 will in principlespring back when they are relieved of load, whereby all energy storedtherein would be released. This could result in the occurrence of greatforces, whereby the frame could be greatly accelerated. In order toprevent this, damping means 35 are also arranged between contactelements 26 and frame 3. These damping means 35, here in the form ofhydraulic cylinders 36, the piston rods 37 of which are connected tocontact elements 26, are each arranged in the shown embodiment in thehigh part of cross beam 9, whereby they can have a considerable volumeand can therefore bring about a high degree of damping. Uncontrolledspringing-back of spring means 31 and contact elements 26 is avoided dueto this damping. Furthermore, the movement of the frame when landing oncontainer 2 is hereby braked more smoothly than would be possible on thebasis of the deformation of contact elements 26 and spring means 31.

Owing to contact elements 26, supplemented here with spring means 31 anddamping means 35, the downward movement of frame 3 is thus braked as itmakes contact with container(s) 2, whereby the occurring loads, andthereby also the noise, remain limited. Twist-locks 11 are moreoverhereby pulled smoothly into corner castings 21 when hoisting begins, sothat the noise is here also limited.

Although the invention is elucidated above on the basis of anembodiment, it will be apparent that it is not limited thereto. Thecontact elements could thus take a movable instead of a deformable form.Movements other than the shown pivoting movement can also be envisaged,for instance a vertical sliding movement. In addition, other springand/or damping means can of course be applied, whether of hydraulic,pneumatic or mechanical type. The scope of the invention is thereforedefined solely by the appended claims.

1. A device for gripping containers from above, comprising: asubstantially horizontal frame having a plurality of corners, the framebeing suspended from a plurality of substantially vertical cables; aplurality of twist-locks, each twist-lock arranged substantiallyadjacent one of the corners of the frame for gripping an upper corner ofthe containers, each twist-lock including a substantially verticalshank; and at least one L-shaped contact element comprising asubstantially horizontal first leg having opposite first and second endsand a substantially vertical second leg having opposite first and secondends, the first and second legs being rigidly connected to each other attheir second ends, the first end of the substantially horizontal firstleg being connected to the frame and the substantially vertical secondleg extending downward from its second end that is rigidly connected tothe substantially horizontal first leg, wherein the at least oneL-shaped contact element is biased to a position in which itssubstantially vertical second leg protrudes substantially parallel tothe shanks of the twist-locks and at least partially under the frame andwherein the at least one L-shaped contact element is adapted to brake amovement of the frame parallel to the cables in the vicinity of acontainer when the frame is placed thereon and the first end of thesecond leg of the at least one L-shaped contact element contacts thecontainer, by absorbing at least a portion of kinetic energy of theframe through controlled deformation or movement of the at least oneL-shaped contact element.
 2. The container gripping device as claimed inclaim 1, comprising a plurality of contact elements, each arranged inthe vicinity of a corner of the frame.
 3. The container gripping deviceas claimed in claim 1, wherein the frame includes an inner area and anouter area, and wherein the first leg of the at least one contactelement is arranged one of in and on the frame and wherein the secondleg protrudes below the frame through an opening formed in the frame. 4.The container gripping device as claimed in claim 3, wherein the firstend of the first leg of the at least one contact element is rigidlymounted to the frame and wherein the at least one contact element iselastically deformable.
 5. The container gripping device as claimed inclaim 3, wherein the at least one contact element is pivotally connectedto the frame.
 6. The container gripping device as claimed in claim 3,wherein the at least one contact element is biased by spring meansarranged between the frame and the contact element.
 7. The containergripping device as claimed in claim 3, further comprising damping meansarranged between the frame and the at least one contact element.
 8. Thecontainer gripping device as claimed in claim 1, wherein the first endof the first leg of the at least one contact element is rigidly mountedto the frame and wherein the at least one contact element is elasticallydeformable.
 9. The container gripping device as claimed in claim 8,wherein the at least one contact element is pivotally connected to theframe.
 10. The container gripping device as claimed in claim 8, whereinthe at least one contact element is biased by spring means arrangedbetween the frame and the contact element.
 11. The container grippingdevice as claimed in claim 1, wherein the at least one contact elementis pivotally connected to the frame.
 12. The container gripping deviceas claimed in claim 11, wherein the at least one contact element isbiased by spring means arranged between the frame and the contactelement.
 13. The container gripping device as claimed in claim 1,wherein the at least one contact element is biased by spring meansarranged between the frame and the contact element.
 14. The containergripping device as claimed in claim 1, further comprising damping meansarranged between the frame and the at least one contact element.
 15. Thecontainer gripping device as claimed in claim 14, wherein the dampingmeans are at least partly accommodated in an upper area of the frame.16. The device as claimed in claim 1, wherein the first and second legsof the L-shaped contact element are integrally formed.
 17. A device forgripping containers from above, comprising: a substantially horizontalframe having a plurality of corners; a plurality of twist-locks, eachtwist-lock arranged close to one of the corners of the frame forgripping an upper corner of the containers; and a plurality of L-shapedcontact elements, each of the plurality of contact elements arranged inthe vicinity of a corner of the frame; wherein each L-shaped contactelement has a substantially horizontal first leg and a substantiallyvertical second leg rigidly connected to the first leg and extendingdownward therefrom, an end part of the substantially horizontal firstleg opposite the rigid connection with the substantially vertical secondleg being connected to the frame; wherein each L-shaped contact elementis biased to a position in which the substantially vertical seconds legthereof protrudes at least partially under the frame and is adapted tobrake a vertical movement of the frame in the vicinity of a containerwhen the frame is placed thereon and the substantially vertical secondlegs of the L-shaped contact elements contact the container, byabsorbing at least a portion of kinetic energy of the frame throughcontrolled deformation or movement of the L-shaped contact elements. 18.The container gripping device as claimed in claim 17, wherein the frameincludes an inner area and an outer area, and wherein the first leg ofeach of the plurality of contact elements is arranged one of in or onthe frame and wherein the second leg protrudes below the frame throughan opening formed in the frame.
 19. The container gripping device asclaimed in claim 17, wherein each of the plurality of contact elementsis elastically deformable and has its first end part rigidly mounted tothe frame.
 20. The container gripping device as claimed in claim 17,wherein each of the plurality of contact elements is pivotally connectedto the frame.
 21. The container gripping device as claimed in claim 17,wherein each of the plurality of contact elements is biased by springmeans arranged between the frame and the respective contact element. 22.The container gripping device as claimed in claim 17, further comprisingdamping means arranged between the frame and each of the plurality ofcontact elements.
 23. The device as claimed in claim 17, wherein thefirst and second legs of the L-shaped contact element are integrallyformed.
 24. A device for gripping containers from above, comprising: asubstantially horizontal frame having a plurality of corners; meansarranged close to each of the corners of the frame for gripping an uppercorner of the containers; and at least one L-shaped contact elementcomprising a substantially horizontal first leg having one end connectedto the frame separately from the gripping means and a substantiallyvertical second leg rigidly connected to the first leg opposite itsconnection to the frame and extending downwardly from said first leg,wherein the at least one L-shaped contact element is biased to aposition in which its substantially vertical second leg protrudes atleast partially under the frame and wherein the at least one L-shapedcontact element is adapted to brake a vertical movement of the frame inthe vicinity of a container when the frame is placed thereon and thesecond leg of the at least one L-shaped contact element contacts thecontainer, by absorbing at least a portion of kinetic energy of theframe through controlled deformation or movement of the at least oneL-shaped contact element.
 25. The device as claimed in claim 24, whereinthe first and second legs of the L-shaped contact element are integrallyformed.
 26. A device for gripping containers from above, comprising: asubstantially horizontal frame having a plurality of corners; aplurality of twist-locks, each twist-lock fixedly mounted on the framesubstantially adjacent one of the corners of said frame; at least oneL-shaped contact element comprising a substantially horizontal first leghaving an end connected to the frame and a substantially vertical secondleg rigidly connected to the first leg at an end opposite the connectionto the frame, the second leg extending downward from the first leg, theat least one L-shaped contact element being biased to a position inwhich its second leg protrudes at least partially under the frame;wherein the at least one L-shaped contact element is deformable ormoveable independently from the twist-locks, so as to brake a verticalmovement of the frame when the frame is placed on a container and thesecond leg of the at least one L-shaped contact element contacts thecontainer, by absorbing at least a portion of kinetic energy of theframe through controlled deformation or movement of the at least oneL-shaped contact element, while the twist-locks remain stationary withrespect to the frame.
 27. The device as claimed in claim 26, wherein thefirst and second legs of the L-shaped contact element are integrallyformed.